This invention relates to the design and efficient industrial manufacturing of soft magnetic core components for an electric modulated pole machine by use of a powder forming process. An efficient routine to manufacture such a structure may be the use of a soft magnetic composite (SMC) material that is based on soft magnetic powder particles that are compacted and deformed in a tool to create a component at relatively high density and including an electrically resistive property of the particles that will reduce the eddy-currents in the material and bring final component properties comparable to electrical steel sheets measured in their most desired direction and using alternating field (AC) magnetisation. Each SMC component can be formed with the described routine into a complex geometrical structure that will enable significant reduction of the number of individual components required to form the desired mono polar machine core.
When designing an electric modulated pole machine for industrial manufacturing there is a known general problem to manufacture the required quite complex soft magnetic components in an efficient way. More specifically the problem is connected to the number of and the complexity of each soft magnetic component that is required to establish an efficient magnetic flux path and a minimal magnetic circuit reluctance that will maximise the specific performance of the machine. The effective flux path must, in the here described machine, be carried by the soft magnetic components in all three geometrical space dimensions. The core material is traditionally a stack of laminated electric steel that is characterised by its high permeability in the plane of each lamina and with a significantly lower permeability in the direction transverse to this plane caused by the interrupts of the soft magnetic steel by the insulation in-between these steel sheets.
These circumstances require e.g. bending of the steel sheet stack to bring an efficient flux path in all three geometrical space dimensions. Another solution may be to divide the soft magnetic core into several sections that could be assembled to form the desired structure. The described state of art techniques do suffer from the drawback of in-efficient manufacturing and handling of a significant number of individual components including the forming and arrangement of the in many cases high number of individual steel sheet laminas.
One known efficient routine is to split the stator core into two or more mostly circular components that are made of soft magnetic powder metal and separately compacted to shape in a press tool. The minimum of two stator sections are then joined in a second operation to form the desired shape of the desired stator core.